Water quality improvement in Little Arkansas River Watershed

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(Note: The following article is based on a news release by Kaitlin Morgan, K-State Research and Extension communications specialist.)

Located in central Kansas, the Little Arkansas River watershed is one of the most intensive agricultural watersheds in the state, with 97 percent of its land area in agricultural production.           

Many of these acres are used for either corn or grain sorghum production and a majority of producers in the watershed use atrazine for control of broadleaf weeds and grasses.           

Because atrazine is water soluble, atrazine can run off fields during rainfall, sometimes creating a surface water quality issue in the Little Arkansas River watershed and other heavily farmed watersheds.      

Spring and early summer are periods of heavy atrazine application due to corn and sorghum planting. As a result, the concentration of atrazine in the surface waters during this season can sometimes rise above the drinking water maximum contaminant level and the aquatic life standards for atrazine set by the U.S. Environmental Protection Agency.

Wichita has an aquifer re-charge project in which they are attempting to capture water during high flow conditions of the Little Arkansas River and inject it back into the groundwater aquifer for later use.   

Before it can be injected, the water must meet drinking water standards. However, most municipal water treatment plants do not remove atrazine and other pesticides because it requires an activated carbon treatment system to the treatment process, which increases the cost of the facility and the day-to-day cost of water treatment.

The Little Arkansas Watershed is currently the only one focusing on this in Kansas.  Other parts of the state may not be aware of some of the issues with atrazine, but in the Little Arkansas Watershed there is a heightened responsiveness because of the city of Wichita. 

Incentive for change

In 2004, a local group of watershed stakeholders developed a plan to restore and protect the surface waters of the Little Arkansas River watershed. The main goal of their Watershed Restoration and Protection Strategy (WRAPS) is to encourage farmers to minimize atrazine loss from crop fields, thereby reducing atrazine runoff to surface waters to levels that meet water quality standards.

The WRAPS team knew atrazine runoff couldn’t be totally eliminated, but if atrazine runoff could be kept at a minimum and spikes in atrazine concentration could be prevented, that would be a tremendous benefit to the city of Wichita in terms of the amount of money it spends treating the water.

Our approach with this WRAPS uses best management practices developed to minimize atrazine runoff to establish a cafeteria-style incentive program for producers to select the practices that fit best to their unique operations. 

We don’t say “in this field you can’t use atrazine.” We present producers with a list of things they can do to help reduce runoff, and see if one or two of those practices will fit into their operations.

The flexibility offered by the program is a crucial part of its success and sets it apart from traditional farm programs. 

By using a dollar-per-acre figure, producers know up front that what they do will dictate the amount of financial incentive they receive. Producers who stop using atrazine will get the full amount of incentive while those who choose a practice predicted to result in a 50 percent reduction of atrazine runoff will receive 50 percent of the incentive dollars available per acre. 


Over the past 10 years, members of the WRAPS team have made extensive education efforts to reach out to local producers in terms of meetings, letters, one-on-one consultations, farm visits, and newsletters.

In the first few years we learned pretty quickly that crop consultants and chemical dealers were key to the success of the project.  We met with those in our area to make sure they know what results we were seeing. 

When the incentive program first started in 2006, there were 41 farmers in the program and best management practices were implemented on 4,792 acres of land in committed watersheds. The result was18 percent less atrazine used. In 2013 the program included 103 farmers, 19,544 acres of land with implemented best management practices, and a 52 percent decrease in the amount of atrazine used.

Water samples taken from a paired watershed monitoring system in the targeted areas have shown dramatic improvements in the amount of atrazine concentration levels in surface water, with the improvement in some years as high as 60 percent. 

We’ve been doing this effort long enough now that some producers are using these practices without any incentives.

The city of Wichita has been happy with the participation rate and the reduced levels of atrazine found in streams and rivers in the area. In 2006, the WRAPS team approached the city of Wichita to ask for financial support and received $10,000, which was matched by another source. The city’s financial donation has grown to $50,000 for incentives as well as providing all the water analysis needed, representing an estimated total contribution of $75,000 per year.

For more information, see K-State Research and Extension publication MF-2768, Atrazine Herbicide Best Management Practices for the Little Arkansas River Watershed at www.ksre.ksu.edu/bookstore/pubs/MF2768.pdf.


Ron Graber, Central Kansas Watershed Specialist